JPS6143503A - Molding method of ligneous synthetic molded article - Google Patents

Abstract

PURPOSE:To prevent a warp of a molded plate by removing residual stress, by a method wherein sanding of the surface is performed by heating and cooling a thermoplastic resin molding material having a neutralized cellulose series pulverized cellulose series pulverized aggregate and a hot molding is performed by providing a kerf on the surface of the molding material. CONSTITUTION:An aggregate (a) is an article to be obtained by a method wherein wood uinegar in a cellulose material is neutralized and room generating wood uinegar gas at the time of resin molding after that is eliminated and a ligneous synthetic molded article A is obtained by performing the resin molding by mixing an appropriate quantity of the aggregate (a) with thermoplastic resin material (b). The molded article A is so constituted that it is cured after it has been heated and amount corresponding to the surface (x) of the molded article A is removed by sanding treatment so that a (y) part is exposed directly as the external surface. Kerfs c-c are provided through appropriate intervals on the surface of the embossed ligneous synthetic molded article A' to be obtained by applying embossing molding to the ligneous synthetic molded article A, whose (x) part of the surface has been removed, by a hot and cold presses. With this construction, inner residual stress in the ligneous synthetic molded article A' is removed and generation of a warp and twist in the synthetic plate A' are prevented effectively.

Description

Detailed Description of the Invention (Industrial Field of Application) This invention is aimed at eliminating internal residual stress in thermoplastic synthetic resin moldings containing wood flour, rice husk flour, bakasu flour, and other cellulose-based fine aggregates. The purpose of this invention is to eliminate the occurrence of distortion in resin molded products and to provide wood synthetic molded products that are free from molding distortion and are suitable for various purposes.

(Prior art) In general, synthetic resin molded products have variations in composition such as density due to the relationship with the materials used and the molding conditions, and residual internal stress due to the molding conditions during molding. It is something that The problem of residual internal stress is that the molded product may warp or twist during cooling shrinkage after molding, shrinkage over time, or expansion and contraction due to temperature changes.

As a means of preventing such molded products from warping or twisting, attempts have been made to mix various aggregates into resin molded products, and this has been found to be quite effective depending on the purpose of use. It is something that was given.

However, if the resin molded product is a plate material, etc.
It is difficult to correct the distortion of the molded product due to the mixing of aggregate, which often causes problems such as warping and twisting.

(Problems to be Solved) In the present invention, a large amount of aggregate is mixed into the resin molding with the intention of preventing the distortion of the resin molding in the past. It is intended to remove residual internal stress in resin molded products containing a large amount of cellulosic aggregate.

In other words, if a large amount of cellulose aggregate is mixed into a resin molded product, this mixed aggregate will extremely inhibit the fluidity of the molded resin, and as a result, it will cause more residual stress than expected in the resin molded product. This is what happened.

If the oscillating internal residual stress is left as it is, the molded product will become distorted in the direction of the stress, causing many inconveniences in use.

Such residual internal stress is caused even more by the fact that the direction of the residual stress is not necessarily constant because the flowability of the molding resin is inhibited due to the mixing of cellulose aggregate, which causes pulsations in the molding resin. This caused inconvenience.

In addition, the problem of residual internal stress becomes even more noticeable when the resin molding is subjected to secondary processing, and when the resin molding is reprocessed by hot pressing, etc. , the product warped and twisted more than expected.

The wooden synthetic shapes and articles according to the present invention include such resin molded articles,
Particularly, to remove residual stress in resin molded plates containing a large amount of cellulose aggregate, and to prevent distortion of the molded plates when they are visually used or used as beads for further processing. This is what I did.

(Means for Solving the Problem) The wooden synthetic product according to the present invention has the following features in particular: 1. A thermoplastic resin molding material containing neutralized cellulose-based fine powder aggregate is heated and cooled, the surface is sanded, grooves are provided on the surface of the molding material, and the material is heated and molded. This provides a wood composite product that does not retain stress.

As a result, not only can the molded wood composite be used as is, but even if it is molded using hot press, etc., the reprocessed product will not warp or twist, ensuring good use. It is what was done.

(Embodiment) A typical embodiment of the present invention will be described below with reference to the accompanying drawings.

First, the aggregate a to be mixed in the molding of the wood composite is a cellulosic material such as wood chips, bulbs, bakasu, or rice husks with an air-dried moisture content within the range. After measuring the weakening of the tissue, a urea-based resin solution is attached and impregnated into the tissue and heated to 100-200℃.
Heating, drying, and pulverization are performed within a temperature range of .

During the impregnation and heating pulverization of the urea-based resin liquid, the wood acid in the material is neutralized, eliminating the possibility of wood acid gas being generated during subsequent resin molding. Furthermore, by impregnating, impregnating, hardening and crushing the urea-based resin liquid, each aggregate a has a hardened urea-based resin material portion, which prevents the inconvenience of re-absorption of moisture in the cellulosic material and improves the bone structure. This material is made by adding appropriate lubricity to material a.

Next, as another method for forming aggregate a, a treatment liquid that absorbs and discharges acidic gases such as monoethanolamine and triethanolamine as the temperature changes is applied to the cellulose material, which is then heated and crushed. As a result, neutralized fine aggregate was obtained separately.

The need to prepare the aggregate a for molding in the following is to remove the wood acid gas generated from the cellulose aggregate a mixed into the resin molding process in advance, and to prepare the aggregate a for resin molding. The purpose is to prevent damage to the molding machine and ensure smooth resin molding.

- In other words, in resin molding, when cellulose aggregate a is mixed into a resin material and then heated and molded, more wood acid gas and water vapor are generated than the mixed aggregate a, and this wood acid The gas and water vapor caused various negative effects on the molding machine and the product. In particular, the wood acid gas and water vapor generated corrode and damage the cylinder, cylinder die, cylinder screw, etc. of the molding machine, and also cause bubbles and rough surfaces of the product.

In addition, since the aggregate to be mixed has been pre-cured with a urea-based resin liquid, it is said that the mixed aggregate has good lubricity and mixes well with the resin material. Not only that, but also there is little frictional resistance with the molding surface of the molding machine during molding, making it possible to perform good extrusion or injection.

A suitable amount of aggregate A thus provided was mixed into a thermoplastic resin material in consideration of the intended molded product and the molding method, and resin molding was performed to obtain a wood composite molded product A. .

In addition, in this resin molding, it was planned to provide a wood composite molded product A using various methods similar to the molding of general molded products, such as adding a foaming agent or a coloring agent to this resin material. It is something.

140 to 300 of the wood composite A thus formed.
After heating in a temperature range of 100°C, the material is cured for 5 to 6 hours in a temperature range of around 100°C to remove the initial shrinkage strain. Quenching of healing resin is
It is designed to take out in advance the distortion caused by the residual stress existing inside the wood composite A, the density of the structure, etc.

In this way, shrinkage distortion, etc. are minimized, and the wood composite molded product is prevented from warping or twisting due to subsequent resin molding or shrinkage over time.

The X portion of the surface of the wood composite A, which is a resin molded product that has been hardened in this way, is removed by sanding, so that the Y portion is directly exposed as the outer surface.

The removal of the surface X portion is intended to remove the portion where the resin material is dense, as is clear from the illustrated example. That is, in resin molding with aggregate a mixed in, the resin in the aggregate a oozes out onto the surface of the molded product, creating a cloth portion of the resin material on this surface.

In addition, the V part of the resin material is a part where internal stress is particularly left due to the difference between the density or the flow direction due to the pulsation of the resin material during molding and the direction perpendicular to the flow. It is something.

Therefore, sanding and removing this surface X part has particular meaning, and from the wood composite A which has sufficiently corrected the distortion,
When this surface portion X is removed, the internal residual stress is almost eliminated.

In this way, the wood composite material A from which the surface X portion was removed was molded using hot press and cold press, and the decorative boards, doors, and other moldings were provided as the wood composite material A°. be.

Next, kerfs c-c are provided on the surface of the wood composite A at appropriate intervals, and the kerfs c-c further cut the stress remaining in the wood composite A. It has been done.

That is, by providing the kerf c-c in a direction perpendicular to the direction in which residual stress is occurring, that is, in a direction that cuts this residual stress, the stress remaining in the wood composite A is separated. This prevents the composite from warping or twisting during subsequent molding.

Note that this kerf c-c is prepared, for example, in a 2 mm thick wooden composite material A with a cutting ratio of about 1.5 mm, and the kerf cc is prepared at a rate of about 1.5 mm in the wood composite material A having a thickness of 2 mm, and this kerf groove is used in the subsequent resin molding. The bond between c and c re-fuses, and almost no loss in strength is observed in the woody synthetic material itself.

(Effects) The wooden composite molded product according to the present invention is expected to have the following effects due to the characteristic structure described above.

That is, (1) The internal residual stress in the molded wood composite A° was removed, and the warping and twisting of the composite board A° was effectively prevented.

(2) Shrinkage distortion in the wood composite material A" was prevented, and the composite board A° was prevented from warping and twisting due to shrinkage.

(3) Aggregate a such as wood powder is exposed on the surface of the wood composite A', giving it a wood-like texture, and its slight moisture absorption function may cause sweating or perspiration on the contact surface. prevented.

(4) Since the aggregate a was exposed on the surface of the wood composite A°, it was said that the abrasion resistance was good and a suitable contact resistance was provided.

(5) Since the aggregate a was exposed on the surface of the wood composite A', it was found that the adhesion of printing ink and spray paint was good.

CB) Aggregate a was exposed on the surface of the wood composite A°, and there was no warping or twisting, indicating that the adhesion was good.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an enlarged cross-sectional view of the main part of a wood composite A according to the present invention, FIG. 2 is an enlarged cross-sectional view of the same with the surface portion removed, and FIG.
The figure is a perspective view of the molded product. In the figure, a indicates an aggregate material, and b indicates a resin material.

Claims (4)

[Claims] (1) A thermoplastic resin molded material containing a neutralized cellulose-based fine aggregate is heated and cooled, the surface is sanded, and grooves are provided on the surface of the molded material to perform hot molding. Characteristic method for forming wood composites. (2) The method for forming a wood composite according to claim 1, characterized in that the aggregate has an average particle size of 100 mesh or more and a water content of 3 cm or less. (3) A method for molding a wood synthetic material according to claim 1, wherein the neutralization is performed by impregnating a urea resin and heating. (4) The wood synthetic material according to claim 1, characterized in that the neutralization is carried out by impregnating and heating a treatment liquid having the function of absorbing and discharging acidic gases such as monoethanolamine and triethanolamine. How to form shapes.